Electric heating-plug



J. W. FRASER.

ELECTRIC HEATING PLUG.

APPLICATION FILED MAR. 18, I920.

Patented Dec. 13, 1921.

Gum "44,5

PATENT OFFICE.

JOHN W. FRASER, OF CLEVELAND, OHIO.

ELECTRIC HEATING-PL G.

Specification of Letters Patent.

Application filed- March 18, 1920. Serial No. 366,914.

specification.

The primary object of the invention is to provide an electrical heating element in the form of a plug adapted to be introduced through an opening in the .wall of the water threaded opening in a metal wall.

prising a round rod or screw 8 and a thin jacket of.an engine or other hollow body containing water or a liquid which is to be heated, all as hereinafter shown and described and more particularly pointed out in the claims.

In the drawing accompanying this application, Figure l is a reduced view of an 1nternal combustion engine showing the water jacket thereof in section and also showing my improved heating plug in place therein. Fig. 2 is a side view of a complete heating lug. Fig. 3 is a side View of the porcelain Eody of the plug and the side terminal thereon. Fig. 4 is a longitudinal section of the metal shell for the plug. Fig. 5 is 'a plan view of the side terminal as it appears before it is bent and mounted on'a porcelain body. Fig. 6 is a sectional view of the plug enlarged and showing it in a osition about to be entered and screwed wlthin a screw- The invention comprises a tapered cylindrical body 2 made of porcelain or other vitreous or electrical non-conducting material. This tapered body is reduced in diameter for a portion of its length: to provide an annular recess 3, an outer flange 4:, and an inner shoulder 5. An insulating compound or electrical non-conducting material 6 together with an electrical resistance 0011 7 is laid or placed within this recess 3 and the opposite ends of the resistance wire connect with separate terminal members comfiat metal piece 9, respectively. The latter is in the form of a loop ,or flat ring 10 adapted to sleeve over the round boss or extension 11 at the larger end of tapered body, 2, and includes a narrow blade or strap 12 which has a prong 14: struck up at its outer end to receive and hold one end of the resistance wire 7 when said strap is laid flat along one side of the body. A notch 15 is also provided in the side of the body 2 into which the outer end of the strap 12 is adapted to project when bent at substantially right a ngles to the side of the body. In assembling the device the wire may be first affixed to the strap by prong 14 and then the ring 10 may be sleeved over or placed in looped connection with projection 11 before wrapping or coiling the resistance wire around the reduced end of the body within or upon a layer of insulating material. Finally the opposite end of the resistance wire is turned laterally into a side slot 16 in flange 4 and in the outer end of body 2 where a round recess 17 is provided to recede a washer 18 and the head 19 of screw 8 between which the end of the wire is wrapped and held. The opposite end of screw 8 extends beyond the projection 11 and is screw-threaded to receive a washer 20, a locknut 21, and a terminal or binding nut 22. Having the arts assembled as described a thin brass she I 23 havin a taper corresponding to the taper of bo y 2 and closed at its smaller end, is sleeved over. the tapered body. The annular edge 24 at the open end of the shell is then flanged or bent inwardly around the shoulder 25 of the body, thereby securing the shell in place and in covering relation to the resistance wire and the head of the screw and with the side of the shell incontact with substantially the entire length of strap 12, but with the head 19 of screw 8 spaced apart from the bottom or end of the shell and preferably insulated therefrom by a thin disk 29 of insulating material.

A plug constructed as described may be wedged tightly within around opening in a metal wall and effect a water tight joint and a firm attachment, but to promote and absolutely assure such a connection I provide the shell 23 with a thin band 26 of solder or other soft pliable metal so that a screwthreaded attachment may be made with a wall 27 having an opening 28 with screwthreads. That is to say, it is not necessary with a soft band or layer .of solder to provide threads on the plug itself'as the band of solder can be screwed into the threaded opening and an exceptionally tight and firm attachment obtained, especially if the plug is tapered and the band of solder also tapered.

One place of utility for heating a plug of the kind described is in connection with internal combustion engines. Thus, the wall of the water jacket of an engine of that kind may be provided with a screw-threaded open- Patented Dec. 13, 1921.

ing and the plug fixed therein where it may be removed at will or remain'permanently. An electrical conductor may then be attached to thescr'ew' 8 and connected with a source of electric current capableof heating the coil 7 and therethrough the thin metal shell and the water within the water jacket. The turning on of the electric current is only resorted to when the water in the circulatory system of the engine is exposed to low temperatures and when the engine is not runmng. However, the device is not restricted incasingsaid body and wire, a terminal 'mem- I ber extending through said body electrically connected with one end of said wire, and the opposite end of said wire coil having an electrical connection with said shell.

3. An electric heating plug, comprising a tapered body of insulating material having a reduced annular portion, an electric resistance coil surrounding said reduced annular portion, atapered shell inclosing said body and coil, a separate terminal member for said coil in electrical contact with said shell, and a-terminal screw connected with the opposite end of said coil and extending centrally through said body having binding medians for an electrical conductor at its outer en 4. An electric heating plug, comprising a body of electric non-conducting material, a terminal member extending through said body, a terminal strap aflixed to the side of said body, a resistance wire coiled around said body having its opposite ends connected with said terminal member, and strap, and a thin metal shell inclosing said body and resistance wire.

5. An electric heating plug, comprising a body having a reduced extremity, a terminal member extending through said body, an

vwire.

electric resistance wire coiled upon said body and having one end connected with said terminal member and the opposite end provided with a loop connected with said extremity, and a thin metal shell inclosing said body and wire and the. connecting ends of said 6. An electric heating plug, comprising a tapered body having a reduced extremity, a metal strap having a ring portion in looped connection with said extremity, an electric resistance coil upon said body and connected with said strap, a terminal member extending through said body and connected with said'coil, and a tapered metal shell inclosing said coil andbody.

7. An electric'heating plug, comprising a body having an electric resistance c011 wound thereon and a metal shell electrically connected with said coil and inclosing said coil and body having an annular band of ductile metal adapted to provide a watertight seal and locking attachment for the p 8. An electric heating plug, comprising a tapered body having an electr c resistance coil wound thereon and provided with a tapered inclosing shell electrically connected with said coil and having a layer of soft metal encircling said shell.

9. An electric heating plug, comprising a tapered body of vitreous material having a reduced annular portion and an end recess and a central opening, a terminal strap detachably connected with said body, a terminal member extending through said central opening, an electric resistance coil wound around said reduced portion having its opposite ends united to said terminal members, and a tapered metal shell inclosing said body having an annular band of ductile metal thereon.

10. An electric heating plug, comprising a resistance coil and a metal inclosing shell therefor having a band of ductile metal thereon in electrical conducting association with said coil, in combination with a wall JOHN W. FRASER. 

